In a hydraulic excavator as an example of a construction machine, a vehicle body generally includes a lower traveling body capable of self-traveling and an upper slewing body slewably mounted on the lower traveling body. The front of the upper slewing body is provided with a working device for carrying out excavation etc.
JP 2015-140641 A discloses an upper slewing body including a slewing frame (i.e., a vehicle body frame) as a structure for supporting a cab, an engine, a hydraulic pump, and the like. An exhaust gas aftertreatment device is connected to the exhaust side of the engine through an exhaust pipe. The exhaust gas aftertreatment device is supported on an aftertreatment device mount provided on the stewing frame.
When a diesel engine is used as the engine, the exhaust gas aftertreatment device may be a urea-selective catalytic reduction (SCR) system. This type of exhaust gas aftertreatment device tends to be large to meet recent exhaust gas regulations, and its weight is also increasing. In order to stably support such a heavy exhaust gas aftertreatment device, the aftertreatment device mount includes an iron mount top plate for supporting the exhaust gas aftertreatment device. A technique in which a mount top plate has sufficient rigidity by providing the mount top plate with an increased thickness dimension has been known.
However, increasing the rigidity of the mount top plate by providing the mount top plate with an increased thickness dimension also results in an increase in weight of the mount top plate itself. This undesirably increases the weight of the entire construction machine.
In view of the above, an object of the present invention is to provide a construction machine in which the weight of a top plate of an aftertreatment device mount is reduced while enhancing the rigidity of the top plate.